The dual role of indicators in optimal fisheries management strategies

Indicators are used in two different ways in the assessment and advisory cycle. One is to audit performance of the management plan relative to achieving the objectives for the fishery. The second is to trigger control rules to manage the subsequent harvest. Traditionally, the assessment and management community has used spawning-stock biomass and fishing mortality for these functions, and as management strategies are being developed, generally continues to test the same indicators in both the audit and control functions. There is no reason to use the same indicators in both functions, and management of a few specialized commercial fisheries has recognized this, using different indicators in different roles for many years. That different indicators may be optimal for both roles presents a richer range of opportunities for exploring robust management strategies, and will be essential as ecosystem considerations and integrated management tools are included in assessment and management.